The present invention relates generally to an equipment support pad, and in particular to a lightweight equipment support pad having a hard shell and generally hollow interior.
The high cost of concrete bases or pads poured on-site for various types of air conditioning, heating, and electrical equipment has given rise to a growing market for pre-cast concrete pads. Such pre-cast pads are usually less expensive than on-site poured pads; however they are generally very heavy and require heavy equipment or several laborers to set in place. Furthermore, such pads are expensive to ship and are prone to breakage.
Certain composite pads have been suggested for replacing the pre-cast concrete pads. For instance, U.S. Pat. No. 4,186,536 shows a pad having a foam core encapsulated in reinforced cementious material. U.S. Pat. No. 4,056,251 discloses a lightweight plastic transformer pad formed of plastic or other synthetic material having an upper surface and lower surface defining an internal cavity. A heat expansive foam material is poured into the cavity.
U.S. Pat. No. 4,505,449 suggests a composite pad having an expanded foam core, such as polystyrene foam board, with a fiber glass reinforced cement material forming a solid base. Steel coils are embedded in the composite material for reinforcing steel post or the like which serve to mount air conditioners or other heavy equipment.
U.S. Pat. No. 5,333,830 discloses a support pad having a cellular core member laminated between a top facing sheet and a bottom facing sheet. The core member is embedded in a cementious shell material defining the support surface. The cellular core member may be formed of paper or other fibrous material and the cellular structure offers a relatively high degree of rigidity and structural support without adding unnecessary weight to the support pad.
The industry is constantly seeking improvements in support pads to reduce weight without sacrificing strength or capacity, while also reducing the cost and complexity of such support pads.
An additional problem frequently encountered with conventional support pads utilizing foam or fibrous core members, particularly in relative hot climates such as the southeastern United States, is that insects and rodents seem to find the form or cellulose core materials attractive for nests, etc. For example, the support pads utilizing foam cores are particularly attractive to fire ants, which tend to break up the core material and carry away the small foam core particles. In certain instances, the ants have carried the particles into the controls of the air conditioner compressor, or other equipment, which has actually caused the equipment to shut down. Field mice and other small rodents have been known to build nests in the cellular core members of the type of support pad described in U.S. Pat. No. 5,333,830.
The present invention provides an alternative cementious support pad having an improved lightweight core that does not detrimentally affect the rigidity and structural integrity of the pad, yet which is relatively inexpensive and easy to manufacture while at the same time being unattractive to pests, rodents, and the like.